The present invention is directed towards optimizing lengths of data packets in wireless sensor networks in order to minimize energy and memory usage. More particularly, the present invention provides a system and method for forming application dependent dynamic data packets for use in wireless sensor networks.
A wireless sensor network (WSN) is a wireless network comprising a mesh of sensor nodes also termed as motes. Each sensor node is equipped with one or more sensors as well as a radio transceiver or other wireless communications device, a small processing unit, and an energy source, usually a battery. The sensor nodes are typically used to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants, at different locations. In its early stages of development a wireless sensor network was used only in military applications such as battlefield surveillance. However, in present times wireless sensor networks are used in a multitude of civilian application areas, such as environment and habitat monitoring, healthcare applications, home automation, and traffic control. Specific applications for WSNs include habitat monitoring, object tracking, nuclear reactor control, fire detection, and traffic monitoring. In recent times WSNs have been successfully deployed in retail stores, industrial automation applications, building automation applications, asset tracking and supply chain management applications. In a typical application, a WSN is employed in an area for collecting data via its sensor nodes.
In a typical WSN a mesh network of sensor nodes are connected to a base station. An individual sensor node is connected to the outside world via the base station. Further, a user can control any particular sensor node by using the base station. Thus a base station acts as a gateway for all communication between a user and a sensor node. The base station also acts as a computational platform for aggregating/processing the data collected by each sensor node and presenting the processed data to an end user. Each sensor employed in a sensor node senses a physical event. The sensed information is converted into digital data which is routed to the base station in the form of data packets. Typically the formation of data packets and their routing is carried out by the processing unit available at the sensor nodes.
In most WSNs data packets having a fixed/predetermined length are used, wherein a typical data packet consists of a start bit, an optional header field, a fixed length payload field, an error correction bit and an end bit. In various cases, for a given application the data sensed by only some of the sensors available in a sensor node is required to be routed. However, while using a fixed length data packet format, data sensed by all the sensors present in the sensor node is included in the data packet. This leads to redundant information being processed and routed by the processing unit.
Sensor nodes are usually very small in size and it is desirable to reduce their sizes still further. Hence, resources such as power/energy, memory, computational speed and bandwidth are available in constrained magnitudes. Processing and routing of redundant information leads to unnecessary drain on the limited resources available with a sensor node.
Consequently, there is need for a system and a method for optimizing resource usage in a sensor node. Further, there is a need for a system and method of using dynamic length data packets for routing only the required information, and eliminating unnecessary information, without adding to the processing complexity. Dynamic length data packet formats would enable conserving power and memory available to a processing unit in a sensor node.